Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2013

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Components of net periodic benefit cost

The components of net periodic benefit cost for the three months endedJune 30 were as follows ($ in millions):

	Pension benefits						Other retirement benefits				Total
	2013			2012			2013		2012		2013			2012
Service cost	$	2.5		$	2.3		$	0.3	$	0.4	$	2.8		$	2.7
Interest cost	3.7			3.8			0.3		0.2		4.0			4.0
Expected return on assets	(4.3		)	(4.1		)	—		—		(4.3		)	(4.1		)
Amortization of prior service credit	(0.3		)	(0.4		)	—		—		(0.3		)	(0.4		)
Recognized actuarial losses	2.3			2.2			—		—		2.3			2.2
Net periodic benefit cost	$	3.9		$	3.8		$	0.6	$	0.6	$	4.5		$	4.4

	Pension benefits				Other retirement benefits				Total
	2013		2012		2013		2012		2013		2012
U.S. plans	$	3.1	$	3.2	$	0.6	$	0.6	$	3.7	$	3.8
International plans	0.8		0.6		—		—		0.8		0.6
Net periodic benefit cost	$	3.9	$	3.8	$	0.6	$	0.6	$	4.5	$	4.4

The components of net periodic benefit cost for the six months ended June 30 were as follows ($ in millions):

	Pension benefits						Other retirement benefits				Total
	2013			2012			2013		2012		2013			2012
Service cost	$	5.0		$	4.6		$	0.7	$	0.7	$	5.7		$	5.3
Interest cost	7.4			7.7			0.5		0.5		7.9			8.2
Expected return on assets	(8.6		)	(8.1		)	—		—		(8.6		)	(8.1		)
Amortization of transition obligation	0.1			—			—		—		0.1			—
Amortization of prior service credit	(0.7		)	(0.8		)	—		—		(0.7		)	(0.8		)
Recognized actuarial losses	4.7			4.3			—		—		4.7			4.3
Net periodic benefit cost	$	7.9		$	7.7		$	1.2	$	1.2	$	9.1		$	8.9

	Pension benefits				Other retirement benefits				Total
	2013		2012		2013		2012		2013		2012
U.S. plans	$	6.3	$	6.4	$	1.2	$	1.2	$	7.5	$	7.6
International plans	1.6		1.3		—		—		1.6		1.3
Net periodic benefit cost	$	7.9	$	7.7	$	1.2	$	1.2	$	9.1	$	8.9